Can Electric Fields Alone Levitate a Train?

AI Thread Summary
The discussion centers on the feasibility of levitating a train using only electric fields, without magnetic fields. It is established that this is technically impossible since every electric field generates a magnetic field. The conversation references the principles of Gauss' Law and Laplace's Equation, which indicate that in a charge-free region, there are no potential minima or maxima to support levitation. Participants express concerns about the practicality of creating a sufficient electric field and the implications of current discharges. Overall, the consensus is that magnetic fields are essential for achieving levitation in trains.
hypnotik
Messages
3
Reaction score
0
Hey guys.
Im currently troubled with a physics theory that i can't explain, or prove.
The question:

Discuss whether it would be possible to design a similar train (Magnetic Levitated Train) by putting the electric field to use (and not using a magnetic field at all).


So i have to see if its possible to create a leviated train, with just the use of Electric Fields, and no magnetic fields. This is technically impossible because every electric field induces a magnetic field. Correct?

I need some more detailed insight on this question though.
Thankyou in advance for your help.

hypnotik'
 
Physics news on Phys.org
well, wouldn't a huge electric field like that make current discharges in the surrounding?

trains are pretty heavy...

but don't count my opinion on it, I am still learning physics
 
Maglev trains can achieve high speeds because they are not limited by friction forces. This is because the train does not sit on the rails, instead it is suspended above them (Hence Maglev: MAGnetic LEVitation).

While magnetic fields can be used to contain charged particles (and thus suspend the trains in midair), electric fields cannot. For a region of space with no free charges, Gauss' Law becomes;

\nabla \cdot \vec{E} = 0

Since, by definition,

\vec{E} = -\nabla V

Gauss' Law can therefore be written in terms of V

\nabla^2V = 0

This is Laplace's Equation. Laplace's equation implies, that for a region of space with no charge, there are no potential minima or maxima. Thus there is no region in space where the train can sit, it will be pushed one way or the other until it enters a region with a non-zero charge density.

Claude.
 
Last edited by a moderator:
Are you sure that is the correct understanding?

Could oyu provide more backing?..

thanks a lot for your effort.

hypnotik'
 
actually that explanation is clear enough, thank you

hypnotik'
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...

Similar threads

Back
Top